Introduction
Determining single culture populations is an arduous task. Conventional methods require manual pipetting and are not real-time in nature. The iGEM IISc 2017 team solved this issue by automating the process and making it real-time which resulted in the GCODe mini and pro.
Our project requires us to determine populations of two different bacteria in the same medium in real time. Faced with this unprecedented task, we set out to explore various methods of conventional population determination methods that could potentially be used in tandem to yield a system of equations to solve the problem at hand.
How did we go about it?
After many extensive brainstorming and research sessions on various physical measurables of the bacteria, we decided to pursue impedance, OD measurement and viscosity methods initially and experimentally verify their feasibility.
Very soon, viscosity measurements seemed infeasible for various reasons:
- Highly medium and preparation-dependence
- Clumping of bacteria at high concentrations
- Extremely difficult to correct for errors caused by the incubator
Our preliminary tests of OD measurements were not promising either.
Asking for Help
Faced with a bleak situation, we met with multiple professors at IISc for ideas and inspiration. Prof. Aloke Kumar provided useful insights (transcript here) and mentioned that Zeta potential would be a great measurable for our system and that it can also be done in real-time with good accuracy. He also showed us an unrelated paper which had used zeta potential measurements.
Simultaneously, we sought assistance from Prof. Hardik Pandya, IISc to help design and build an apparatus to measure the impedances of samples in real time.
Hence, OptoMatic is being developed based on a modified GCODe structure to incorporate the impedance.
